Turntable drive



Feb. 28,1933

TURNTABLE DRIVE Filed Oct. 8, 1930 V Y 7 %W/////////////////////////////ff//////////////// ///nmmumm INVENTOR Ben amm Rcarson.

BY? I A TTORNE Y B. R. CARSON 1,899,669 v Patented Feb. 1933 UNITE STATES -IBE'NJ'AIIN B. CARSON, OF OOLLINGSWOOD, NEW JERSEY, ASSIGNOB, BY HESNE AS- SIG'IQ'MIEN'JSS, T RADIO CORPORATION OF AMERICA, 01 NEW YORK, N. Y., A. COB

PORATION OF DELAWARE PATENT or-'1=1c1:-:

TURNTABLE DRIVE Application flled october 8, 1930. Serial No. 487,115.

My invention relates to phonographs and it has particular relation to turntable drive mechanism therefor.

In the majority of phonographs now in use, the turntable is, usually, positively secured to a turntable support and drive spindle to which a governor-controlled prime ,mover, revolving at the required turntable speed, is directly connected.

Under certain circumstances, it is desirable to utilize a prime mover of the constant speed type havin a high turning torque. A prifilne mover of t is character is, of necessity, a 1100 R. P. M.

To utilize such a motor for driving a phonograph turntable, usually at aspeed of 78 to 80 R. P. M., it is necessary to interpose a reduction gear mechanism between the motor and the turntable-driving spindle. In such cases, it is not desirable to have the turntable positively connected to, the driving spindle therefor, since the momentum of the revolving turntable would tend to cause damage to the reduction gear' mechanism when the motor is abruptly stopped.

It is, accordingly, the primary object of my invention to obviate this difiiculty and to provide a phonograph drive which will permit continued rotation of the turntable, although the driving motor may have stopped, without any damaging effects on the interposed reduction gearing.

Bother object of my invention is to provide a phonograph drive mechanism which is capable of driving the turntable positively under'certain conditions, but capable also, when necessary, of permitting relative movement between the turntable and its spindle.

r A further object of my .invention is to provide a phonograph drive mechanism whereby the turntable may continue to rotate substantially freely and may. come to rest graduallyand smoothly after the spindle has stopped rotating.

Still another object of my invention is to provide a phonograph drive mechanism wherein a yieldable drive is capable of automatic change to a positive drive and vice gh speed motor usually rated at-about versa when the speeds of the turntable and its spindle vary.

More specifically stated, it is an object of my invention to rovide a. turntable drive mechanism for p onographs whereby, un-.

der normal operating conditions the turntable may be driven throu h one coupling, while under abnormal condltions, as, for example, in home recording of a special record where the stylus drag imposes an addidrawing in which:

Fig. 1 is a 88013101181 view of a turntable and drive mechanism therefor embodying the elements of my invention.

Fi 2 is a sectional view on a line correspon ing to the line 2-2 of Fig. 1.

Fig. 3 is a plan view looking down on the turntable drive mechanism with the turntable removed.

Fig. 4is an enlarged fragmentary sectional view illustrating the relativeposition 'of the positive turntable drive pins in driving position, and

Fig. 5 is an enlarged fragmentary sectional view illustrating t e manner in which the yieldable pin carried by the turntable passes over the fixed driving pin when the turntable is rotating relative to the spindle.

Referring to the drawing, the apparatus shown in Fig. 1 comprises a prime mover 10 which may be of the constant speed type with a reduction gear mechanism 11 coupled thereto. A spindle 12, having one end thereof operatively connected to said reduction gear mechanism 11, projects upwardly therefrom at right angles to the axis of the prime I mover 10. r

Secured to the spindle 12 ad acent the free end thereof, by means of a set screw 13, is a collar 14 having an annular recess 15 formed.

in the upper face thereof for the reception of a loosely fitted washer or annulus 16 of suitable friction materialhaving a thickness.

on the upper end of said spindle with the face of said boss contacting with the friction washer 16, whereby the turntable may be rotated in response to the spindle operating through the said frictlon washer. The construction so far set forth in detail constitutes the means for frictionally driving the turntable and for permitting relatlve rotary movement thereof with respect to the spindle after the spindle has come to rest.

The positive drive element, which is combined with the said friction drive element interposed between the turntable 17 and spindle 12 consists of a driving pin 19 which is seated or doweled vertically in the collar 14 within the confines of the friction washer-16 but spaced radially from the spindle 12. The

in 19 is preferably fixed by means of a drive fit in the collar 14, said pin projecting upwardly beyond the face of the annular recess 15. The projecting free end of the drive pin 19 is formed so as to have a flat, inclined top surface 20 for a purpose to be presently set forth.

The turntable 17 is provided with a counterbored opening. 21 extending down from the upper surface thereof through the boss 18. The counterbored opening 21 is so formed as to receive a shouldered pin 22, together with a spring 23, a headless set screw 24 being threaded into said opening 21 for retaining said spring and pin therein. With the pin 22 so positioned in the turntable 17, the lower, free end thereof will depend below the face of the boss 18 whereby the said pin 22 is yieldably disposed in the path of the fixed pin 19.

It will, therefore, be obvious that when the pin 19 engages the pin 22, a positlve drive is maintained between the spindle 12 and turntable 17 ,each rotating at identically the same speed. However, should the turntable rotate at a speed greater than the speed of the spindle 12, or should the turntable con; tinue to rotate, due to its momentum, when the spindle has stopped, each timethe pin 22 reaches the pin 19, it will yieldably ride over the inclined surface 20 thereof until, under the frictional force of washer 16, the turn- 7 table will gradually and smoothly slow down -to the speed of the spindle or come to a complete. stop, as the case may be.

Although I have shown and described one specific embodiment of my invention, I am fully aware that many modifications thereof are possible. I, therefore, do not wish to be restricted to the specific structure, details and arrangement of parts 'herein set forth, but

desire that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In combination, a spindle having a collar secured thereto and having a recess therein, friction means in said recess, a supportingmember freely mounted on said spmdle and being adapted to be driven by the action of said friction means upon rotation of said spindle, and additional drivin means comprising a pair of pins acting to rive said supporting member when its s eed falls below that of said spindle, one 0 said pins being further adapted to yield under the action of the other pin to permit rotation of said supporting member after said spindle has come to rest. 1

2. In combination, a spindle having a collar attached thereto, a supporting member freely mounted on said spindle, friction means disposed between said collar and supporting member for normally driving said member upon rotation of said spindle, and additional driving means comprising a pair of contacting pins one of which is adapted to yield under the action of the other to permit rotation of said supporting member after the driving pin has come to rest.

3. In combination, a spindle having a collar attached thereto, a supporting member freely mounted on said spindle, friction means disposed between said collar and the supporting member for normally driving said member in response to said spindle, and additional driving means comprising a pair of cooperating pins, one of which is fixed and is carried b said collar, and the other is carried by sai supporting member and is yieldable under the action of said fixed pinto permit rotation of said member after said spindle has come to rest.

4. In combination, a rotatable spindle having a shoulder formed thereon, a rotatable support loosel mounted on said spindle, friction means dlsposed between said shoulder and support for normally drivin said support in response upon rotation 0 said spindle, and additional driving means comprising a pair of cooperating pins, the opposed ends of said pins being shaped to permit relative movement therebetween in one direction of rotation when said support is rotating faster than said spindle and to prevent relative movement therebetween in the same direction when both said support and said splndle are moving at the same speed.

5. In combination, a spindle having a recessed collar secured thereto, friction means in said recess, a rotatable member having a boss on the underside thereof loosely mounted on said spindle with the face of said boss in contact with said friction means, afixed upstanding pin carried by said collar, :1 yieldable pin carried by said boss and normally extending into the path of said fixed pin for engagement therewith to positively drive said member-upon rotation of said spindle when the'speed of said member falls below that of said spindle, and means whereby said yieldable pin is urged upwardly to permit rotation of said member after said spindle and fixed pin have come to rest.

6. In combination, a spindle, a collar carried by said spindle, a rotatable member having a hub formed on the underside thereof loosely mounted on said spindle, friction means interposed between said collar and hub for driving said member upon rotation of said spindle, and positive drive 5 means comprising an upstanding pin carried by said collar and a second pin depending from said hub adapted to engage said first named pin to supplement the driving action of said friction ring when the speed of said '20 member drops below that of said spindle.

7 In combination, a spindle, a collar carried by said spindle, a rotatable member having a'hub formed on the underside thereof loosely mounted, on said spindle, friction means interposed between said collar and hub for rotating said member in response to said spindle, and positive drive means comprising a fixed pin carried by said collar and a yieldable pin carried by said hub,'said pinsbein adapted for engagement to supplement sai friction means when the s eed of said member drops below that of said spindle.

In testimony whereof, I have hereunto subscribed my name this second day of October,

BENJAMIN R. CARSON. 

